call dibs (on something)
slang To claim the right to do or choose something first before others. “Dibs” is a shortening of “dibstones,” counters used in an 18th-century children’s game.
Hey, I called dibs on sitting in the front seat of the car!
Whoever calls dibs can have this last piece of cake.
Sally called dibs on this one, so you’ll have to pick a different one.